IMMUNOLOGY Flashcards
How many % of anaphylactic episodes is uniphasic and biphasic?
a. 80-90% uniphasic
b. 10-20% biphasic
Most common presentations of anaphylaxis (>90% of cases)
Cutaneous manifestation
Severe hymenoptera-induced anaphylaxis can be a presenting feature of what underlying condition?
Systemic mastocytosis
What is the mechanism involved when a repeated exposure to an allergen induces anaphylaxis?
IgE – mediated (usually with antibiotics and chemotherapy)
Paclitaxel-induced anaphylaxis: IgE or non-IgE-mediated?
Non-IgE
Radiocontrast-induced anaphylaxis: IgE or non-IgE-mediated?
Non-IgE
Vancomycin-induced anaphylaxis: IgE or non-IgE-mediated?
Non-IgE
Opiates-induced anaphylaxis: IgE or non-IgE-mediated?
Non-IgE
NSAIDs-induced anaphylaxis: IgE or non-IgE-mediated?
Non-IgE
Onset of symptoms and signs of anaphylaxis occurs within seconds to minutes after the trigger, except for:
Delayed anaphylaxis to meats in alpha-gal sensitized patients
Most obvious biomarker of anaphylaxis:
Histamine (but with extremely short half-life)
More practical and useful biomarker of anaphylaxis
Serum tryptase
Treatment of anaphylaxis and dose:
Epinephrine – 0.3-0.5 mL of 1:1000 (1 mg/mL) IM with repeated doses at 5-20 min intervals as needed for a severe reaction
Body posture that may lead to “empty heart syndrome” in anaphylaxis
Upright or sitting posture
Recommended body position before receiving epinephrine in anaphylaxis
Supine position
Simplest, most straightforward approach to long-term management of a patient with a history of anaphylaxis
Avoidance
Study stating that early introduction of peanut protein to the diet of high-risk infants can prevent development of most (80% or more) peanut allergy
Learning Early About Peanut Allergy (LEAP) study
Premedication regimens for radiocontrast allergy with doses and timing (2):
a. Prednisone 0.5 mg/kg at 13, 6, and 1 h prior to contrast administration
b. Diphenhydramine – 25 mg 1 h prior to contrast
Management of flushing reactions from vancomycin (2):
a. Antihistamine premedication
b. Downtitrate infusion rate
Refers to a group of autoantibody-mediated intraepidermal blistering diseases characterized by loss of cohesion between epidermal cells
Pemphigus
Loss of cohesion between epidermal cells is a process termed
Acantholysis
Manual pressure to the skin of pemphigus patients may elicit the separation of the epidermis. This is called
Nikolsky’s sign
Mucocutaneous blistering disease that predominantly occurs in patients >40 years of age and typically begins on mucosal surfaces and often progresses to involve the skin.
This disease is characterized by fragile, flaccid blisters that rupture to produce extensive denudation of mucous membranes and skin
Pemphigus vulgaris (PV)
The mouth, scalp, face, neck, axilla, groin, and trunk are typically involved
Crusts and shallow erosions on scalp, central face, upper chest, and back
Pemphigus foliaceus
Painful stomatitis with papulosquamous or lichenoid eruptions that may progress to blisters
Paraneoplastic pemphigus
Large tense blisters on flexor surfaces and trunk with histologic finding of subepidermal blister with eosinophil-rich infiltrate
Bullous pemphigoid
Pruritic, urticarial plaques rimmed by vesicles and bullae on the trunk and extremities with the histologic findings of teardrop-shaped, subepidermal blisters in dermal papillae; eosinophil- rich infiltrate
Pemphigoid gestationis
Extremely pruritic small papules and vesicles on elbows, knees, buttocks, and posterior neck with histology of subepidermal blister with neutrophils in dermal papillae and with granular deposits of IgA in dermal papillae
Dermatitis herpetiformis
Blisters, erosions, scars, and milia on sites exposed to trauma; widespread, inflammatory, tense blisters may be seen initially
Epidermolysis bullosa acquisita
Dermatomyositis often involves the hands as erythematous flat-topped papules over the knuckles. What do you call this papules?
Gottron’s papules
Patients with Pemphigus vulgaris have IgG autoantibodies to
desmogleins (Dsgs)
transmembrane desmosomal glycoproteins that belong to the cadherin family of calcium-dependent adhesion molecules
early PV – Dsg3
Advanced PV – Dsg3 and Dsg1
Bad prognostic factors for pemphigus vulgaris
- Advanced age
- Widespread involvement
- Requirement for high doses of glucocorticoids
mainstay of treatment for pemphigus vulgaris
Systemic glucocorticoids
moderate to severe PV - prednisone at 1 mg/kg/day
may be combined with immunosuppressive agents such as azathioprine, mycophenolate mofetil, rituximab, or cyclophosphamide
Treatment of severe or progressive pemphigus vulgaris
Plasmaperesis or IV Ig
Pemphigus wherein acantholytic blisters are located high within the epidermis, usually just beneath the stratum corneum
Pemphigus foliaceus
Which is more superficial: Pemphigus foliaceus or vulgaris?
Pemphigus foliaceus
In terms of mucous membrane involvement, differentiate Pemphigus foliaceus and vulgaris
Foliaceus – mucous membrane is almost always spared
Vulgaris - mucous membrane is usually involved
Mild cases of pemphigus foliaceus can resemble
severe seborrheic dermatitis
Direct immunofluorescence microscopy of perilesional skin ofpemphigus vulgaris and foliaceus demonstrates ___ on the surface of keratinocytes
IgG
In pemphigus foliaceus, autoantibodies are directed against
Dsg1
Although pemphigus has been associated with several autoimmune diseases, its association with _____ and/or ______ is particularly notable
Thymoma
myasthenia gravis
T or F. Drug-induced pemphigus usually resembles PV rather than PF
False. drug-induced pemphigus usually resembles PF rather than PV
T or F. Pemphigus foliaceus is generally a less severe disease than PV and usually carries a better prognosis
True
An autoimmune acantholytic mucocutaneous disease associated with an occult or confirmed neoplasm
Paraneoplastic pemphigus (PNP)
The predominant neoplasms associated with paraneoplastic pemphigus are (6)
- non-Hodgkin’s lymphoma
- Chronic lymphocytic leukemia
- Thymoma
- Spindle cell tumor
- Waldenström’s macroglobulinemia
- Castleman’s disease (children with PNP)
In addition to severe skin lesions, many patients with paraneoplastic pemphigus develop life-threatening
bronchiolitis obliterans
A polymorphic autoimmune subepidermal blistering disease usually seen in the elderly that evolve from urticarial plaques to tense blisters on either normal-appearing or erythematous skin
Bullous pemphigoid
The lesions are usually distributed over the lower abdomen, groin, and flexor surface of the extremities
The major histocompatibility complex class II allele _______ is prevalent in patients with bullous pemphigoid
HLA-DQβ1*0301
Direct immunofluorescence microscopy of normal-appearing perilesional skin from patients with this condition shows linear deposits of IgG and/ or C3 in the epidermal basement membrane
Bullous pemphigoid
An alternative immunofluorescence microscopy test substrate used to distinguish circulating IgG autoantibodies to the basement membrane in patients with bullous pemphigoid from those in patients with similar, yet different, subepidermal blistering diseases
1 M NaCl split skin
mainstay of treatment of bullous pemphigoid
Systemic glucocorticoids
A rare, nonviral, subepidermal blistering disease of pregnancy and the puerperium
Pemphigoid gestationis
any trimester of pregnancy or present shortly after delivery
Immunologically-mediated skin condition that is almost always extremely pruritic
Pemphigoid gestationis
Linear deposits of C3 in the epidermal basement membrane is an immunopathologic hallmark of this disorder
Pemphigoid gestationis
A subepidermal bullous disease that resembles pemphigoid gestationis clinically, histologically, and immunopathologically
Bullous pemphigoid
An intensely pruritic, papulovesicular skin disease characterized by lesions symmetrically distributed over extensor surfaces (i.e., elbows, knees, buttocks, back, scalp, and posterior neck)
Dermatitis herpetiformis
pruritus has a distinctive burning or stinging component
Almost all dermatitis patients have associated (usually subclinical) GI condition. This is the
gluten-sensitive enteropathy
The major histocompatibility complex class II allele that is present in >90% or dermatitis herpetiformis (2)
HLA-B8/DRw3 and HLA-DQw2
Subepidermal blistering disorder that is confirmed by direct immunofluorescence microscopy of normal-appearing perilesional skin and granular deposits of IgA (with or without complement components) in the papillary dermis and along the epidermal basement membrane zone
Dermatitis herpetiformis
If maintained, this diet alone may control the skin disease in dermatitis herpetiformis and eventuate in clearance of IgA deposits from these patients’ epidermal basement membrane zones
Gluten-free diet
Mainstay of treatment of dermatitis herpetiformis
Dapsone
Patients respond rapidly (24–48 h) to dapsone (50–200 mg/d), but require careful pretreatment evaluation and close follow-up to ensure that complications are avoided or controlled
All patients taking dapsone at _____ will have some _____ and______ , which are expected pharmacologic side effects of this agent
> 100 mg/d
Hemolysis
Methemoglobinemia
Difference of linear IgA disease from dermatitis herpetiformis (2)
Do not have increased frequency of HLA-B8/DRw3 haplotype or an associated gluten-sensitive enteropathy
Treatment of linear IgA disease
Dapsone
A rare, noninherited, polymorphic, chronic, subepidermal blistering disease characterized by blisters on noninflamed skin, atrophic scars, milia, nail dystrophy, and oral lesions
Epidermolysis bullosa acquisita
Subepidermal blistering disease that is considered as a mechanobullous disease
Epidermolysis bullosa acquisita
The major histocompatibility complex class II allele that is found in epidermolysis bullosa acquisita
HLA-DR2 haplotype
Epidermolysis bullosa acquisita is associated with what GI condition
IBD (esp. Crohn’s disease)
Subepidermal blistering disease that is largely resistant to treatment
chronic, noninflammatory form of epidermolysis bullosa acquisita
although some patients may respond to cyclosporine, azathioprine, IVIg, or rituximab
inflammatory form may respond to systemic glucocorticoids
A rare, acquired, subepithelial immunobullous disease that commonly involve the oral mucosa (esp. the gingiva) and conjunctiva that is characterized by erosive lesions of mucous membranes and skin that result in scarring of at least some sites of involvement
Mucous membrane pemphigoid
typically a chronic and progressive disorder
Studies suggest that mucous membrane pemphigoid
patients with autoantibodies to ____ have an increased relative risk for cancer
laminin-332
Heliotrope erythema is seen in what condition
Dermatomyositis
purple-red discoloration of the upper eyelids, sometimes associated with scaling and periorbital edema
“heliotrope” erythema
The most common cutaneous manifestation of dermatomyositis
“heliotrope” erythema
Pathognomonic for dermatomyositis
Gottron’s papules
These lesions can be contrasted with the erythema and scaling on the dorsum of the fingers that spares the skin over the interphalangeal joints of some SLE patients
Thin violaceous papules and plaques on the elbows and knees of patients with dermatomyositis are referred to as
Gottron’s sign
T or F. Poikiloderma is a common feature seen SLE, scleroderma and dermatomyositis
False. Poikiloderma is rare in both SLE and scleroderma and thus can serve as a clinical sign that distinguishes dermatomyositis from these two diseases
Acute cutaneous LE is characterized by
erythema of the nose and malar eminences in a “butterfly” distribution
Characterized by a widespread photosensitive, nonscarring eruption that may present as a papulosquamous eruption that resembles psoriasis or as annular polycyclic lesions
Subacute cutaneous lupus erythematosus (SCLE)
Autoantibodies in subacute cutaneous lupus erythematosus (SCLE)
Ant-Ro
Characterized by discrete lesions, most often found on the face, scalp, and/or external ears and present as erythematous papules or plaques with a thick, adherent scale that occludes hair follicles (follicular plugging)
Discoid lupus erythematosus
In this condition, when a scale that occludes hair follicles is removed , its underside shows small excrescences that correlate with the openings of hair follicles (so-called “carpet tacking”)
Discoid lupus erythematosus
A finding relatively specific for DLE
The skin changes of scleroderma usually begin on the (5)
fingers, hands, toes, feet, and face
Sclerodactyly is seen in
Scleroderma
The fingers may shrink and become sausage-shaped, and, because the fingernails are usually unaffected, they may curve over the end of the fingertips. This is seen in
Scleroderma
Facial involvement of this condition includes a smooth, unwrinkled brow, taut skin over the nose, shrinkage of tissue around the mouth, and perioral
radial furrowing
Scleroderma
Cold-induced blanching, cyanosis, and reactive hyperemia that is documented in almost all patients with scleroderma and can precede development of the disease by many years
Raynaud’s phenomenon
CREST syndrome is combination of
Calcinosis cutis Raynaud’s phenomenon Esophageal dysmotility Sclerodactyly Telangiectases
Autoantibodies that is seen in a very high percentage of patients with CREST syndrome but in only a small minority of patients with scleroderma
Anti-centromere
Characterized by localized thickening and sclerosis of skin that is usually located in the trunk
Morphea
T or F. Morphea, unlike scleroderma, is usually quite resistant to therapy
False. Scleroderma and morphea are usually quite resistant to therapy
Treatment options for early, rapidly progressive disease include phototherapy (UVA1 [ultraviolet A1 irradiation] or PUVA [psoralens + ultraviolet A irradiation]) or methotrexate (15–20 mg/week) alone or in combination with daily glucocorticoids
A clinical entity that can sometimes be confused with scleroderma and is characterized by a sudden onset of swelling, induration, and erythema of the extremities, frequently following significant physical exertion
Diffuse fasciitis with eosinophilia
Indurated skin that usually displays a woody, dimpled, or “pseudocellulite” appearance is seen in what condition
Diffuse fasciitis with eosinophilia
Contractures in this immunologic condition may occur early secondary to fascial involvement and may also cause muscle groups to be separated and veins to appear depressed. What do you call this sign and what condition?
Groove sign.
Diffuse fasciitis with eosinophilia
A multisystem disorder with epidemic numbers of cases reported in 1989 and linked to ingestion of l-tryptophan manufactured by a single company in Japan, characterized by debilitating myalgias and absolute eosinophilia in association with varying combinations of arthralgias, pulmonary symptoms, and peripheral edema
eosinophilia-myalgia syndrome
